This invention relates to a cathode-ray tube having an improved implosion-protection system, and particularly an improved double tension band, or double "T-band," as it is called in the art, for implosion protection.
Cathode-ray tubes comprising evacuated glass bulbs are mass-produced articles of commerce. They usually include a faceplate panel hermetically sealed to a funnel. A luminescent screen is carried on the inner surface of the panel, and one or more electron guns are housed in a neck attached to the narrow end of the funnel. Some adverse effects of implosion of the bulb can be reduced or eliminated by providing an implosion protection system around the panel.
Examples of one family of such systems, known generally as double tension band, or double "T-band," systems are described in U.S. Pat. Nos. 3,697,686 to A. Hildebrants and 3,890,464 to M. Hill et al. Prior double T-band systems comprised a plastic or fabric tape encircling the panel, a first tensed steel band on the fabric tape encircling the panel and a second tensed steel band on the first band encircling the panel. The steel bands are usually coated with a zinc or a zinc-and-epoxy coating. These prior double T-band systems provided the required degree of safety to the viewer of the tube. However, it is desirable to provide double T-band systems which are easier and cheaper to manufacture but still provide the required degree of safety to the viewer.